Question

As always, my wife and I are trying to figure out how to get our baby to sleep through the night. Suppose we believe that he sleeps longer if he gets a “dream feed”—a small meal, a couple hours into the night, that he barely wakes up for. We know that, in general, Tony sleeps for 5.5 hours per night. We give him “dream feeds” for 16 nights and find that he slept for 6.5 hours per night, with a sample standard deviation of 2 hours. What are the df and the t-crit value for a test of this data (assume alpha = .05)?

a. Df = 15; t-crit = 2.131

b. Df = 16; t-crit = 2.290

c. None of the options given are correct

d. Df = 8; t-crit = 4.556

Answer 1

Solution :

This is the right tailed test,  

The null and alternative hypothesis is ,

H0 :   = 5.5

Ha : > 5.5

n = 16

D. f. = n - 1 = 16 - 1 = 15

= 0.05  

P(t > t) = 0.05

= 1 - P(t < t) = 0.05

= P(t < t) = 1 - 0.05

= P(t < t ) = 0.95

= P(t < 1.753 ) = 0.95  

critical value t = 1.753

c. None of the options given are correct